Sano was sent down on Monday along with a pair of pitchers, reducing Minnesota's spring training roster to 45. The 21-year-old from the Dominican Republic hit two home runs in 10 at-bats in exhibition games, with three walks in six games.
Sano was bound to start in the minors, after missing last season while recovering from ligament-replacement surgery on his right elbow. The Twins have said there is a possibility he could make his major league debut this year.
In 2013, Sano combined to hit 35 homers in 123 games in Class A and Double-A.